We examined correlates of ischemic episodes in 24-h ambulatory electrocardiograms (ECG) in a sample of 1511 men and women 65 years old and older. Ischemic episodes had a high prevalence period during early afternoon and also during morning hours after awakening, and the overall prevalence was 13% in men and 9% in women (P < 0.001 for gender difference). The prevalence was 9.6% in participants with no history of myocardial infarction and no major or minor resting ECG abnormalities. In multivariate analysis by logistic regression, being on digitalis medication was associated with over a three-fold risk of ischemic episodes, with an odds ratio (95% confidence limits) of 3.21 (1.80 to 5.74). Left ventricular hypertrophy by ECG and atrial fibrillation had almost a three-fold excess risk of ischemic episodes, with odds ratios 2.81 (1.37 to 5.74) and 2.63 (1.17 to 5.91), respectively. Isolated ST-T abnormalities had almost a two-fold excess of ischemic episodes, with an odds ratio of 1.89 (1.01 to 3.54). Being overweight was associated with a 33% reduced likelihood of ischemic episodes after adjustment for other factors, with an odds ratio of 0.67 (0.46 to 0.98). It is concluded that the prevalence of silent ischemic episodes is high in older men and women.